Spaenaur

Technical Data
Suggested Tightening Torque1 Values To Produce Corresponding Bolt Clamping Loads
D
SAE Grade 2 Bolts SAE Grade 5 Bolts SAE Grade 7 3 SAE Grade 8 4
Tensile
Size Bolt Stress Tensile Proof Clamp 2 Tightening Torque Tensile Proof Clamp 2 Tightening Torque Clamp 2 Tightening Torque Clamp 2 Tightening Torque
Dia. Area Strength Load Load Dry Lub. Strength Load Load Dry Lub. Load Dry Lub. Load Dry Lub.
D (in.) A (sq. in.) (min psi) (psi) P (lb.) K=0.20 K=0.15 (min psi) (psi) P (lb.) K=0.20 K=0.15 P (lb.) K=0.20 K=0.15 P (lb.) K=0.20 K=0.15
lb. in. lb. in. lb. in. lb. in. lb. in. lb. in. lb. in. lb. in.
4-40 0.1120 0.00604 74,000 55,000 240 5 4 120,000 85,000 380 8 6 480 11 8 540 12 9
4-48 0.1120 0.00661 280 6 5 420 9 7 520 12 9 600 13 10
6-32 0.1380 0.00909 380 10 8 580 16 12 720 20 15 820 23 17
6-40 0.1380 0.01015 420 12 9 640 18 13 800 22 17 920 25 19
8-32 0.1640 0.01400 580 19 14 900 30 22 1100 36 27 1260 41 31
8-36 0.1640 0.01474 600 20 15 940 31 23 1160 38 29 1320 43 32
10-24 0.1900 0.01750 720 27 21 1120 43 32 1380 52 39 1580 60 45
10-32 0.1900 0.02000 820 31 23 1285 49 36 1580 60 45 1800 68 51
1/4-20 0.2500 0.0318 1320 66 49 2020 96 75 2500 120 96 2860 144 108
1/4-28 0.2500 0.0364 1500 76 56 2320 120 86 2860 144 108 3280 168 120
lb. ft. lb. ft. lb. ft. lb. ft. lb. ft. lb. ft. lb. ft. lb. ft.
5/16-18 0.3125 0.0524 2160 11 8 3340 17 13 4120 21 16 4720 25 18
5/16-24 0.3125 0.0580 2400 12 9 3700 19 14 4560 24 18 5220 25 20
3/8-16 0.3750 0.0775 3200 20 15 4940 30 23 6100 40 30 7000 45 35
3/8-24 0.3750 0.0878 3620 23 17 5600 35 25 6900 45 45 7900 50 35
7/16-14 0.4375 0.1063 4380 30 24 6800 50 35 8400 60 45 9550 70 55
7/16-20 0.4375 0.1187 4900 35 25 7550 55 40 9350 70 50 10700 80 60
1/2-13 0.5000 0.1419 5840 50 35 9050 75 55 11200 95 70 12750 110 80
1/2-20 0.5000 0.1599 6600 55 40 10700 90 65 12600 100 80 14400 120 90
9/16-12 0.5625 0.1820 7500 70 55 11600 110 80 14350 135 100 16400 150 110
9/16-18 0.5625 0.2030 8400 80 60 12950 120 90 16000 150 110 18250 170 130
5/8-11 0.6250 0.2260 9300 100 75 14400 150 110 17800 190 140 20350 220 170
5/8-18 0.6250 0.2560 10600 110 85 16300 170 130 20150 210 160 23000 240 180
3/4-10 0.7500 0.3340 13800 175 130 21300 260 200 26300 320 240 30100 380 280
3/4-16 0.7500 0.3730 15400 195 145 23800 300 220 29400 360 280 33600 420 320
7/8-9 0.8750 0.4620 60,000 33,000 11400 165 125 29400 430 320 36400 520 400 41600 600 460
7/8-14 0.8750 0.5090 12600 185 140 32400 470 350 40100 580 440 45800 660 500
1-8 1.0000 0.6060 15000 250 190 38600 640 480 47700 800 600 54500 900 680
1-12 1.0000 0.6630 16400 270 200 42200 700 530 52200 860 660 59700 1000 740
1-1/8-7 1.1250 0.7630 18900 350 270 105,000 74,000 42300 800 600 60100 1120 840 68700 1280 960
1-1/8-12 1.1250 0.8560 21200 400 300 47500 880 660 67400 1260 940 77000 1440 1080
1-1/4-7 1.2500 0.9690 24000 500 380 53800 1120 840 76300 1580 1100 87200 1820 1360
1-1/4-12 1.2500 1.0730 26600 550 420 59600 1240 920 84500 1760 1320 96600 2000 1500
1-3/8-6 1.3750 1.1550 28600 660 490 64100 1460 1100 91000 2080 1560 104000 2380 1780
1-3/8-12 1.3750 1.3150 32500 740 560 73000 1680 1260 104000 2380 1780 118400 2720 2040
1-1/2-6 1.5000 1.4050 34800 870 650 78000 1940 1460 111000 2780 2080 126500 3160 2360
1-1/2-12 1.5000 1.5800 39100 980 730 87700 2200 1640 124005 3100 2320 142200 3560 2660
Notes:
1. Tightening torque values are calculated from the formula
T = KDP, where T = tightening torque, lb-in.; K = torque-friction
coefficient; D = nominal bolt diameter, in.; and P = bolt clamping
load developed by tightening. lb.
2. Clamp load is also known as preload or initial load in tension on
bolt. Clamp load (lb.) is calculated by arbitrarily assuming usable
bolt strength is 75% of bolt proof load (psi) times tensile stress area
(sq. in.) of threaded section of each bolt size. Higher or lower values
of clamp load can be used depending on the application requirements
and the judgement of the designer.
3. Tensile strength (min psi) of all Grade 7 bolts is 133,000. Proof
load is 105,000 psi.
4. Tensile strength (min psi) of all Grade 8 bolts is 150,000 psi.
Proof load is 120,000 psi.
Ref.: Fastening Reference. Machine Design. Nov. 1977.
Bolt Clamping Force
vs.
Tightening Torque
for
Unlubricated Steel Bolts.
Bolt Clamping Force (lbs.)
10,000
9,000
8,000
7,000
6,000
5,000
4,000
3,000
2,000
1,000
0
5/16" -18
3/8"-16
1/2"- 13
5/8"-11
3/4"-10
0 100 200 300 400 500 600 700 800 900 1000
Tightening Torque (inch-lbs.)
CATALOG 13
D48